Re: Fire In The Wire

Jim Upson
 

Let me be clear.....I am NOT an expert.....and this LONG post may not be what anyone wants.....or may be 'old news' to everyone...or worse may not pass a 'test' by true technical experts....

With the caveats aside......My 3 part response to W0ODJ's question is:
>   Part 1...what I want to do in the <near> future
>   Part 2...what I am using today
>   Part 3...my conclusions....remember, I am not claiming to be an expert...please cut me some slack if I am off base....but also please let me know so I can learn from you and that I don't pollute with bad recommendations....

Part 1:  
I too am on a journey for an effective portable antenna solution....especially for operating portable on SOTA outings where time is in short supply (like when I do attempt to do multiple SOTA Summits in one day).  I have not proven any of these 3 solutions yet, but these are how I plan to focus my experimentation this spring/summer:

First..as backgrond in case you haven't seen this:   Sotabeams did a survey in 2014 and concluded this:   https://www.sotabeams.co.uk/blog/5-most-popular-hf-portable-antennas/  :

#1:  End Fed Half Way (18%)
#2:  Linked Dipole (16%)
#3:  Single Band Dipole (12%)
#4:  Random Length End Fed wire (12%)
#5:  Ground Plane (11%)

So......I've focused my attention towards the various End Fed solutions (Half-wave or Random)...The Half-Waves should be more 'efficient'....while the Random EF's offers greater band hopping versatility...

1)  64:1 solution with a Half Wave wire:  Answers to a very similar question that was posed on the SOTA Reflector:  https://reflector.sota.org.uk/t/kx2-3-w-tuner-owners-what-antenna-do-you-use/16758.   I thought the following from W2USA (at near the end of 67 responses posted) regarding a 64:1 solution was interesting.....see the link embedded in his response regarding N1KDO's 64:1 unun:

Sure, I have a buddy here locally (N1KDO) who has been using and liking this antenna setup with his KX3 for a while and has been encouraging me to give it a try. I finally built the unun pretty much exactly like he has on his website (link: https://www.n1kdo.com/baluns-ununs/index.html 69). It is the last thing on the page. I used a different case than he did, but it is pretty much the same otherwise. I made some small holes in the back of the case and looped a cable tie through it. Then I can velcro the cable tie to the pole, so it is not just hanging there. I dont have any pics of mine, but I will try to snap some next time I have it out.

The radiators are 0.5 wavelength and the counterpoise is 0.25 wavelength. The beauty of that is if you want to use the truly resonant wire for each band (and not have the tuner make up the difference) you can use/resuse wires as radiators and counterpoises. For example, the counterpoise for the 80m wire is the 40m radiator, the counterpoise for the 40m radiator can be used as the 20m radiator, and the 20m counterpoise can be the 10 radiator and so on. Same with 60/30/15. 17m and 12m are the only odd ducks that probably do best with their own set of wires. (I purposefully left out 6m since the KX2 doesnt have 6m :(. haha) So you can bring a whole “set” of wires out there and you will definitely have less than (# of bands)X2 sets of wires. Plus like I was saying before, the tuner can make up the difference as well. I did an activation a couple weeks ago, put the 40m set up, and did really well on both 40 and 20.

Hope that helps some.

-Steve / W2SWA

2)  49:1 solution with a Half-Wave wire:  Peanut Power QRP Multiband EFHW from G0POT... http://peanutpower.co.uk/efhw.    He briefly talks about in this youtube...starting at "1-min: 25-second" mark:    https://www.youtube.com/watch?v=O4nuZq2pcUA

3)  KX0R ...... I consider this guy an true technical expert.....I plan to try to make his solution after the above 2 solutions are first tried as I want to first "build up" my "builder skills".  The following LINK is to a very long article (read that as "with a lot of good details")...and if you subscribe to QRP Quarterly he also recently published it there too....And, If you look over his QRZ page...I think you will the same feeling I get....that he "knows his electrons" very well from both a theoretical and, more importantly, a practical point of view:  Here is KX0R's solution:    https://reflector.sota.org.uk/t/a-versatile-tuner-for-sota-activations-by-kx0r/19748  .  His SOTA scores are impressive....hence his solution is both theoretically and practically proven (at least in my eyes)

4)  I will also try a vertical...these are the one's I am focused on....
     
>   Buddistick:   https://www.youtube.com/watch?v=FVUrx8xL6EA   But if you go with 2 or more counterpoises...and you change bands....then they need to shortened/lengthened and that does not appeal to me on the surface....be sure to read the Buddipole in the Field, by B. Scott Andersen (NE1RD)...starting on page 106.

>  Another sort-of vertical solution is the "Mini Black Widow from WA3WSJ":    https://wa3wsj.homestead.com/UP-Outter_BW_Mini.html  this, I believe will not require re-turning the counterpoises or vertical length to change bands....

>  Finally another version is from QRP-GUYs.... https://qrpguys.com/qrpguys-tri-band-portable-vertical-antenna/nggallery/thumbnails   and following this advice regarding the counterpoise wires found within this SotaReflector posting:   https://reflector.sota.org.uk/t/interesting-new-sota-vertical-antenna/16885  (it's been awhile since I read all of it...but in general I recall 1 or 2 ELEVATED radials will improve its performance compared to the QRPGUY's solution of laying their 4 radials on the ground.

Part-2
For my current portable antenna....I have had what I think is very good success with a 20/40 EFHW (2-bands).....which I bought (not made) from LNR...but now you can buy them from Virbroplex.  This version was developed by Dale Parfitt/W4OP many years ago...and are still quite relevant and popular today...and were originally sold as Par-End-Feds., then LNR sold them, and now Virbroplex has taken over the commerical rights ( http://www.vibroplex.com/contents/en-us/p3413.html )...

I typically hang my 20/40 EFHW on a SOTABEAMS 23' mast (Tactical 7000hds) and just lean it against trees...with the wire oriented as an inverted-v and the ends 3+ feet above ground.  Goes up 'quick' and comes down 'quicker'   :-)     I can also make it a self-standing telescoping pole using this solution:   http://www.qsl.net/wb3gck/guyring.html This works amazingly well....even in some moderately windy conditions.....but I seldom need it unless out in an open field.

Just yesterday (Mar 14) I did a one-day '4-summit blitz' in the SOTA-Pittsburgh PA region (W3/PT)....and with my KX3 (with built-in tuner), 14-watts, and only using SSB....I worked England, Sweden, Germany, Spain, Canada (granted, my signal reports were typically 33 to 44 with some 55+ now and then...but then propagation isn't great either these days)...as well as all across the US (California, Texas, Wisconsin, Tennessee, Florida, NC, NY...etc.)  Here is just one of the 4 summit's log I did yesterday (if you have registered on SOTA, you can see all my contacts from yesterday....

image.png

I also have used in the past (2017 timeframe) a 17-meter Par-EFHW....and got great results across the Arizona, Colorado and west-coast.  Par EFHWs  'just plain work'....

So...1 or 2-bands EFHW works great for me...but of course it is very limiting....and I especially want to also have 60- and 80-meter bands for more close-in contacts...as you can see in my log from yesterday's SOTA outing above...I use the 20/40 on 80-meters with some success...the internal KX3 tuner tunes it to 1:1 or even 1:0.......albeit the signal reports are typically 22-44-ish due to it's shorten length I suppose....hence, I am on a quest for a more versatile solution but one that will minimize the compromises (efficiency losses) given my KX3's max low-power of 15-watts.  See Part-1 above for my "plans".

A friend, Jill N3ICE, was also out doing other summits (W3/SV area) yesterday and her solution is the Packtenna commercial 9:1 version.  With her RANDOM End-Fed APPROXIMATELY 59', and a shorter counterpoise...(I get the actual lengths later if you want them) she was able to work DX (Spain, Germany, Czech Republic, and all across the USA...with KX2 and 10-watts and all SSB......including one Summit-2-Summit with me at 15:07 UTC (signal reports 33 both ways).  

image.png

Part 3
So...what's the bottomline....at least from my neophyte perspective....

>  The 'best' (efficient) antenna is, as we all know, a resonant one...and the general wisdom I've collected on SOTA Reflector or other internet sources says a Linked-Dipole is one of the favorite SOTA antenna solutions..... similar to these commercial offerings from Sotabeams:   https://www.sotabeams.co.uk/four-band-portable-dipole-antenna-system-band-hopper-iv/ .  BUT BUT BUT.......you must get up and off your BUTT to change the links..which probably requires you to lower the telescoping pole...change the link....and re-raise the pole to change bands.....something that is less than exciting (pain in the BUTT) especially when you are in a wooded area and the wires are carefully placed among the tree branches....it's hard enough to be able to get all that wire up to begin with....let along be able to change the links from time to time....Hence, a compromise solution is a preferred approach to the otherwise resonant dipole version.  This is not for me....

> Next 'best' efficiency-based-solution seems to be EFHW's that 'perform' similar to a resonant dipole...because in reality they are (a resonant dipole....Half-Wave length......just fed at one end).  The challenge is to make them multibanded.....and this challenge has 2 options:  one can add links (BUT BUT BUT....), or add traps.  Adding traps are often thought of a 'big compromise'....but Tom W8JI has debunked that issue as not relevant (http://www.w8ji.com/traps.htm ).  Commercial versions of traps are available from Sotabeams...(10, 20 or 100-watt versions).  The limiting factor is that most people recommend to keep the number of traps in a wire to 2 traps (although I forget where I heard this...so I am not sure this is gospel)...giving you 3 bands.  For me, the first trapped EFHW I will make is for an 20, 40, 60 ......with a 49:1 or 64:1 unun near the radio end......I may later try a trap version giving me 4 bands (for 20, 30, 40, 60) when I know Morse Code.....or simply add a link at the end of 40m wire for the  4th band on a 2-trapped EFHW wire.

>>>> Quick note...this is probably not necessary...but....I refer a lot to Sotabeams....I have ZERO interest or stake of any kind with that company...I am just a very satisfied customer over the years...as I am with the 4States offerings...

>  I am surprised your 49:1 isn't working well for you....seems to me that it should be a near ideal solution (effective, fairly efficient and certainly "operator friendly") assuming your antenna is a Half-Wave long.  I'd suggest you maybe should have someone take a look at it with you to see if there is a good reason for it not working well for you.  I personally have very high-hopes for it....or it's cousin the 64:1 version....See "Peanut Power" in Part 1 above.

>  My 'ultimate' plan is the KX0R tuner solution....no traps, no links, one EF Random wire....if building one from scratch seems out of your skill...you might want to consider this excellent 4States QRP Club offering:   http://www.4sqrp.com/4stuner.php  which I THINK mimics closely to the KX0R solution (maybe others can confirm....but that is how I see it).  Here is a Youtube that shows the 4SQRP tuner........ https://www.youtube.com/watch?v=aTHqz4XrVnM

>  Among the EF solutions, for me the last likely solution is a 9:1 solution.....it has the widest range of versatility.....but seems to generate both glowing as well as many rather un-favorable reviews.....but Jill, N3ICE certainly has done very well with her version....Balun Designs has a good reference for lengths to use:   https://www.balundesigns.com/content/Wire%20Lengths%20for%204%20and%209-1%20ununs.pdf   or here:   http://www.hamuniverse.com/randomwireantennalengths.html

I'll throw one last link I've found beneficial me to...I had asked a question on the SOTA reflector regarding when to use Ferrite vs Type 2 or Type 6 Powdered Iron toroids....  https://reflector.sota.org.uk/t/efhw-transformer-toroid-t-6-yellow-or-t-2-red-or-ft-43/18802   skip down to response #35 from KX0R.....and later in response #39.    I found his comment on type 43 toroids particularly interesting in that, at least from a theoretical point of view, and as such, the 49:1 or 64:1 solutions SHOULD NOT be as efficient as his solution discussed above in Part-1 (3rd solution from KX0R)....YET....to me.....there are literally 1000's of hams who give high praises for the 49:1 / 64:1 type of solution typically using a Type-43 toroid....

I also spent a lot of bench time working with type 43 and 61 transformers. Type 43 is so lossy that it’s hard to measure a resonant frequency in a tuned circuit. It’s really designed for broadband transmission line transformers and EMI suppression chokes. It’s not a good choice for conventional transformers. Many of the people posting here don’t seem to know what these terms mean. I would not use type 43 to feed the antenna in my SOTA system. The reason some antennas use it is that its loss hides the mismatch errors in the system! It lowers SWR by adding loss.

I personally do NOT think KX0R is more of a theoretician than a practician...actually I think he is basically both practical (end results oriented) grounded in the theoretical....thus I've chosen to think it's valid (but with my caveats, I have no skills to prove or refute his finding)...

OK...that's given you WAY much reading.....I hope that maybe some of it is useful or possibly new news to you.....but if this is all old news...then all I can say is that I am sorry for taking up so much digital ink....like I said in the beginning...."I too am on a journey...."

I would really like to know where you end up....sharing ideas makes this hobby the best in the world (for me anyway)....

To those with strong technical skills....I would HIGHLY value your response if what I am saying is wrong technically...other otherwise bad advice....I want to be correct....yet I know my serious limitations regarding technical topics....

Humbly,
 72/73, Jim AC3B




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